Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

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Light-emitting diodes

Light emitting diodes reliability review

Heat and fluid flow in high-power LED packaging and applications

Color Conversion Materials for High-Brightness Laser-Driven Solid-State Lighting

Thermal management of electronics: An experimental analysis of triangular, rectangular and circular pin-fin heat sinks for various PCMs

Thermal analysis and optimization of multiple LED packaging based on a general analytical solution

Light-emitting diode (LED) street lamps rely heavily on successful thermal management, which strongly affects the optical extraction and the reliability/durability of the LED lamp. A thermal analysis of an 80 W LED street lamp was done. Sixteen thermocouples were used to measure the temperatures at 16 different positions of the street lamp. The results demonstrated that the temperature of the frame and the heat sink of the 80 W LED street lamp remained stable at about 42degC after several hours of lighting at a room temperature of 11degC, and the bulk material resistance of the heat sink could be neglected. Numerical simulation was also used to analyse the temperature distribution of the lamp. The reliability of the numerical model was proven by a comparison of simulation results with the experimental data. Through simulations and the corresponding analyses it was found that the tested 80 W LED street lamp would have poor reliability at an environment temperature of 45degC.

http://tpl.energy.hust.edu.cn/uploadfile/file/paper%202/2013032708560869.pdf

Thermal analysis of an 80 W light-emitting diode street lamp

Light emitting diodes (LEDs) are now widely used in many fields including traffic lights, vehicle backlights and liquid crystal display (LCD) displays because of their long life, good illumination efficiency and low energy consumption. At present, LEDs are increasingly replacing the traditional lighting and are being used in general illumination such as the street lamp. For the high-power LED street lamps, good light extraction is the most important thing, but low junction temperature of the LED modules is also critical for achieving a long lifetime and a high optical efficiency. Actually, there have been many reports about early failures of street lamps, called dead lamps that have been regarded as a barrier in the public and administration acceptance of LED street lamps. Therefore temperature estimation is always a crucial issue for LED product development. A multi-chip spreading thermal resistance model was applied to estimate the temperature distribution of LED street lamp. The experiment was first done to obtain temperatures of several locations in a prototype LED street lamp. Then the multi-chip spreading resistance model was established to calculate the full temperature distribution. Comparison between the model calculation and experimental measurement showed a good agreement, which demonstrates that the present model can be used in engineering design to estimate the temperature distribution of high-power LED street lamps.

Temperature estimation of high-power light emitting diode street lamp by a multi-chip analytical solution

When junction temperatures of the light emitting diode (LED) chips packaged inside LED lamps exceed their maximal limits, the optical extraction and the reliability/durability of the LED lamps will be jeopardized, therefore, thermal management is very important for high power LED street lamps. In this research, a design and optimization method of horizontally-located plate fin heat sink was presented to improve the heat dissipation of high power LED street lamps. To prove the feasibility of the present design and optimization method, a 112-W LED street lamp was co-designed by concurrent engineering of optical, thermal, and stress requirements. The engineering prototypes were manufactured and experimentally investigated. The experimental results demonstrated that the maximal heat sink temperature remained to be stable at 45°C when the ambient temperature was 25°C, the maximal temperature difference between steady state temperature and environment temperature for the heat sink was less than 21°C. Comparing the results achieved by the design with the ones by the experiment, it is found that the design and optimization method is feasible and works well for realizing the horizontally-located heat sink of such kind of high power LED street lamp.

Design and optimization of horizontally-located plate fin heat sink for high power LED street lamps

Multiple-chip packaging becomes common in LEDs packaging community For such types of packaging, thermal spreading resistance is an important factor to impact the total thermal performance of LEDs In this paper, a general analytical solution based on the method of variable separation for thermal spreading resistances of eccentric heat sources on a rectangular flux channel is used to calculate the whole temperature field of LED packaging substrate The feasibility of the analytical method used in LEDs packaging has been proven by the temperature comparison with existing experimental results of an 80W LED street lamp According to the analytical solution, optimization analysis is presented in order to obtain more uniform temperature distribution on the substrate of the multi-chip LEDs packaging The optimization results can effectively instruct the LED packaging design and reduce the system thermal resistance

Ting Cheng

Papers

Thermal analysis and optimization of multiple LED packaging based on a general analytical solution

Thermal analysis of an 80 W light-emitting diode street lamp

Temperature estimation of high-power light emitting diode street lamp by a multi-chip analytical solution

Design and optimization of horizontally-located plate fin heat sink for high power LED street lamps

Thermal analysis and optimization of multiple LED packaging based on a general analytical solution